1 files changed, 230 insertions, 0 deletions
diff --git a/libpod/networking_linux.go b/libpod/networking_linux.go
new file mode 100644
index 000000000..ee90b765c
--- /dev/null
+++ b/libpod/networking_linux.go
@@ -0,0 +1,230 @@
+// +build linux
+
+package libpod
+
+import (
+	"crypto/rand"
+	"fmt"
+	"net"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+
+	cnitypes "github.com/containernetworking/cni/pkg/types/current"
+	"github.com/containernetworking/plugins/pkg/ns"
+	"github.com/cri-o/ocicni/pkg/ocicni"
+	"github.com/pkg/errors"
+	"github.com/projectatomic/libpod/utils"
+	"github.com/sirupsen/logrus"
+	"github.com/vishvananda/netlink"
+	"golang.org/x/sys/unix"
+)
+
+// Get an OCICNI network config
+func getPodNetwork(id, name, nsPath string, ports []ocicni.PortMapping) ocicni.PodNetwork {
+	return ocicni.PodNetwork{
+		Name:         name,
+		Namespace:    name, // TODO is there something else we should put here? We don't know about Kube namespaces
+		ID:           id,
+		NetNS:        nsPath,
+		PortMappings: ports,
+	}
+}
+
+// Create and configure a new network namespace for a container
+func (r *Runtime) configureNetNS(ctr *Container, ctrNS ns.NetNS) (err error) {
+	podNetwork := getPodNetwork(ctr.ID(), ctr.Name(), ctrNS.Path(), ctr.config.PortMappings)
+
+	result, err := r.netPlugin.SetUpPod(podNetwork)
+	if err != nil {
+		return errors.Wrapf(err, "error configuring network namespace for container %s", ctr.ID())
+	}
+	defer func() {
+		if err != nil {
+			if err2 := r.netPlugin.TearDownPod(podNetwork); err2 != nil {
+				logrus.Errorf("Error tearing down partially created network namespace for container %s: %v", ctr.ID(), err2)
+			}
+		}
+	}()
+
+	logrus.Debugf("Response from CNI plugins: %v", result.String())
+
+	resultStruct, err := cnitypes.GetResult(result)
+	if err != nil {
+		return errors.Wrapf(err, "error parsing result from CNI plugins")
+	}
+
+	ctr.state.NetNS = ctrNS
+	ctr.state.IPs = resultStruct.IPs
+	ctr.state.Routes = resultStruct.Routes
+	ctr.state.Interfaces = resultStruct.Interfaces
+
+	// We need to temporarily use iptables to allow the container
+	// to resolve DNS until this issue is fixed upstream.
+	// https://github.com/containernetworking/plugins/pull/75
+	if resultStruct.IPs != nil {
+		for _, ip := range resultStruct.IPs {
+			if ip.Address.IP.To4() != nil {
+				iptablesDNS("-I", ip.Address.IP.String())
+			}
+		}
+	}
+	return nil
+}
+
+// Create and configure a new network namespace for a container
+func (r *Runtime) createNetNS(ctr *Container) (err error) {
+	ctrNS, err := ns.NewNS()
+	if err != nil {
+		return errors.Wrapf(err, "error creating network namespace for container %s", ctr.ID())
+	}
+	defer func() {
+		if err != nil {
+			if err2 := ctrNS.Close(); err2 != nil {
+				logrus.Errorf("Error closing partially created network namespace for container %s: %v", ctr.ID(), err2)
+			}
+		}
+	}()
+
+	logrus.Debugf("Made network namespace at %s for container %s", ctrNS.Path(), ctr.ID())
+	return r.configureNetNS(ctr, ctrNS)
+}
+
+// Configure the network namespace using the container process
+func (r *Runtime) setupNetNS(ctr *Container) (err error) {
+	nsProcess := fmt.Sprintf("/proc/%d/ns/net", ctr.state.PID)
+
+	b := make([]byte, 16)
+
+	if _, err := rand.Reader.Read(b); err != nil {
+		return errors.Wrapf(err, "failed to generate random netns name")
+	}
+
+	nsPath := fmt.Sprintf("/var/run/netns/cni-%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
+
+	if err := os.MkdirAll(filepath.Dir(nsPath), 0711); err != nil {
+		return errors.Wrapf(err, "cannot create %s", filepath.Dir(nsPath))
+	}
+
+	mountPointFd, err := os.Create(nsPath)
+	if err != nil {
+		return errors.Wrapf(err, "cannot open %s", nsPath)
+	}
+	mountPointFd.Close()
+
+	if err := unix.Mount(nsProcess, nsPath, "none", unix.MS_BIND, ""); err != nil {
+		return errors.Wrapf(err, "cannot mount %s", nsPath)
+	}
+
+	netNS, err := ns.GetNS(nsPath)
+	if err != nil {
+		return err
+	}
+	return r.configureNetNS(ctr, netNS)
+}
+
+// iptablesDNS accepts an arg (-I|-D) and IP address of the container and then
+// generates an iptables command to either add or subtract the needed rule
+func iptablesDNS(arg, ip string) error {
+	iptablesCmd := []string{"-t", "filter", arg, "FORWARD", "-s", ip, "!", "-o", ip, "-j", "ACCEPT"}
+	logrus.Debug("Running iptables command: ", strings.Join(iptablesCmd, " "))
+	_, err := utils.ExecCmd("iptables", iptablesCmd...)
+	if err != nil {
+		logrus.Error(err)
+	}
+	return err
+}
+
+// Join an existing network namespace
+func joinNetNS(path string) (ns.NetNS, error) {
+	ns, err := ns.GetNS(path)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error retrieving network namespace at %s", path)
+	}
+
+	return ns, nil
+}
+
+// Get a container's IP address
+func (r *Runtime) getContainerIP(ctr *Container) (net.IP, error) {
+	if ctr.state.NetNS == nil {
+		return nil, errors.Wrapf(ErrInvalidArg, "container %s has no network namespace, cannot get IP", ctr.ID())
+	}
+
+	podNetwork := getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.PortMappings)
+
+	ipStr, err := r.netPlugin.GetPodNetworkStatus(podNetwork)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error retrieving network status of container %s", ctr.ID())
+	}
+
+	ip := net.ParseIP(ipStr)
+	if ip == nil {
+		return nil, errors.Wrapf(ErrInternal, "error parsing IP address %s for container %s", ipStr, ctr.ID())
+	}
+
+	return ip, nil
+}
+
+// Tear down a network namespace
+func (r *Runtime) teardownNetNS(ctr *Container) error {
+	if ctr.state.NetNS == nil {
+		// The container has no network namespace, we're set
+		return nil
+	}
+
+	// Because we are using iptables to allow the container to resolve DNS
+	// on per IP address, we also need to try to remove the iptables rule
+	// on cleanup. Remove when https://github.com/containernetworking/plugins/pull/75
+	// is merged.
+	for _, ip := range ctr.state.IPs {
+		if ip.Address.IP.To4() != nil {
+			iptablesDNS("-D", ip.Address.IP.String())
+		}
+	}
+
+	logrus.Debugf("Tearing down network namespace at %s for container %s", ctr.state.NetNS.Path(), ctr.ID())
+
+	podNetwork := getPodNetwork(ctr.ID(), ctr.Name(), ctr.state.NetNS.Path(), ctr.config.PortMappings)
+
+	// The network may have already been torn down, so don't fail here, just log
+	if err := r.netPlugin.TearDownPod(podNetwork); err != nil {
+		logrus.Errorf("Failed to tear down network namespace for container %s: %v", ctr.ID(), err)
+	}
+
+	nsPath := ctr.state.NetNS.Path()
+
+	if err := ctr.state.NetNS.Close(); err != nil {
+		return errors.Wrapf(err, "error closing network namespace for container %s", ctr.ID())
+	}
+
+	// We need to unconditionally try to unmount/remove the namespace
+	// because we may be in a separate process from the one that created the
+	// namespace, and Close() will only do that if it is the same process.
+	if err := unix.Unmount(nsPath, unix.MNT_DETACH); err != nil {
+		if err != syscall.EINVAL && err != syscall.ENOENT {
+			return errors.Wrapf(err, "error unmounting network namespace %s for container %s", nsPath, ctr.ID())
+		}
+	}
+	if err := os.RemoveAll(nsPath); err != nil && !os.IsNotExist(err) {
+		return errors.Wrapf(err, "error removing network namespace %s for container %s", nsPath, ctr.ID())
+	}
+
+	ctr.state.NetNS = nil
+
+	return nil
+}
+
+func getContainerNetIO(ctr *Container) (*netlink.LinkStatistics, error) {
+	var netStats *netlink.LinkStatistics
+	err := ns.WithNetNSPath(ctr.state.NetNS.Path(), func(_ ns.NetNS) error {
+		link, err := netlink.LinkByName(ocicni.DefaultInterfaceName)
+		if err != nil {
+			return err
+		}
+		netStats = link.Attrs().Statistics
+		return nil
+	})
+	return netStats, err
+}